The present invention relates to insulation in general and specifically to the reduction of heat transfer from the heater assembly to the handle of a desoldering device.
The manufacture and repair of modern electronic devices requires the ability to solder and unsolder electrical connections on very small devices, for example, printed circuit boards and the like. A device has been developed which not only provides sufficient heat to melt the solder in a soldered junction, but also provides a suction to withdraw melted solder from the area of the joint allowing the parts to be separated even after any solder residue has solidified. Such a desoldering device is described in U.S. Pat. No. 3,392,897 to Siegel issued July 16, 1968.
By reference to FIG. 2 in the Siegel patent, the major components of the desoldering device will be clearly evident. A heater assembly 14 has a small tubular tip inserted in the front end thereof which is heated and serves to conduct sufficient heat to melt the solder at the area of interest. The tip 12 is also in fluid communication through end portion 51 with a solder catcher tube 72 and from there to a vacuum fitting assembly 19. The heater assembly 14 is mounted to a handle assembly 17 by means of a thermal baffle assembly whose function is to reduce as much as possible heat transferred from the heater assembly 14 to the handle 17. Obviously, it is desirable that the handle assembly remain as cool as possible while the heater assembly maintains tip 12 at a sufficient temperature to readily melt solder which is to be removed. The heat path in the prior art is from the heater assembly to the metal plate 18 from there through screws 22, non-metallic plate 20 and through screws 26 into the hollow hub 28. Siegel notes that the primary insulation is the air space provided between metal plate 18 and non-metallic plate 20 although the non-metallic nature of plate 20 will itself serve to provide some insulation.
While the Siegel reference teaches a thermal barrier, under prolonged usage of the device, the handle especially in the vicinity of hub 28 becomes uncomfortably hot degrading operator performance. Additionally, although the use of a non-metallic plate 20 increases the effectiveness of the thermal barrier, it decreases the rigidity between tubular tip 12 and the handle itself. For preciseness of operation, it is desirable that the tip 12 be rigidly coupled to the handle assembly 17. Furthermore, it can be seen that spacers 24 have a minimal surface area allowing essentially all heat conducted into the spacer 24 by screw 22 to be conducted into the non-metallic plate 20.
Thus, even though the Siegel disclosure represented the state-of-the-art at the same time, it had several disadvantages which included only moderate thermal insulation between the heater assembly and the handle and the lack of an extremely rigid coupling between the tubular tip and the handle assembly.